Rain flooded this Mesa neighborhood last year. And it could happen again

In Karen Gleason's mind, the storm was long over.

She'd heard about it all week, as meteorologists tracked Hurricane Norbert's march up the West Coast and forecast its collision with the still-potent dregs of Arizona's fading monsoon.

She'd heard about it that morning, as television channels cycled through endless shots of cars floating down flooded freeways, their shell-shocked drivers clinging to emergency responders.

She, like other parents of Keller Elementary students in Mesa, had opted to keep her daughter home through the worst of the Sept. 8 downpour.

But by early afternoon, the sky had been peaceful for hours, and Karen was comfortably curled up on the living-room couch folding laundry and watching afternoon TV as 10-year-old Sofia caught another show in the bedroom.

Ready to tackle the next chore, the 52-year-old put one bare foot down on the area rug below and felt a squish.

That's strange, she thought. Had she spilled something?

The wet patches she saw spreading across the carpet didn't make sense.

Neither did the water that had begun to seep slowly, then swiftly, across the living room and into every other room of Karen's one-story home just north of U.S. 60, blocks away from Mesa's Emerald Park.

The truth — that the greatest damage caused by the morning's record-breaking deluge didn't arrive until after the storm had ended and the sun was out — would be just as incomprehensible for almost 200 of her neighbors. They watched helplessly as rising floodwaters from the overflowing Emerald Park basin ravaged their homes.

The finger-pointing began even before the murky brown water had receded, a process formalized in a yet-unresolved lawsuit homeowners filed against the city, state and the Arizona Department of Transportation.

Tracing the exact flow of the water that swamped the Emerald Acres area that day is nearly impossible. But a yearlong Arizona Republic review of thousands of pages of engineering records, maintenance logs, reports, analyses, e-mails and photos from Mesa and ADOT shows how human decisions helped set the stage for the disaster.

Two top the list. First, the 1970s-era drainage system fashioned to manage runoff alongside the U.S. 60 was built to a standard less stringent than what is recommended today. And the layout of the area, with its low-set houses and terrain partly graded against the larger region's natural slope, in extreme cases causes water to back up rather than drain away quickly.

Experts who reviewed the events agree the type of storm that can cause a catastrophe like the one seen last September is rare — a one-in-1,000 chance in any given year — but clearly possible.

With the lawsuit pending, city and state officials remain mostly unwilling to comment on their roles in the flood. Documents from this spring show Mesa applied for and secured county funding to help finance flood-control improvements in the neighborhood, but without more information from the city, it's unclear how effective those upgrades will be — and construction isn't anticipated to begin until next year.

What is clear, experts say, is that without a dramatic overhaul of the area's drainage system or a fresh plan to temper its shortcomings, the kind of flood that wrecked Karen Gleason's neighborhood will happen again.

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In the 1970s, as ADOT worked to extend the Superstition Freeway through Mesa, engineers knew the berm planned alongside it would act as a dam during heavy storms.

They designed an interlocking system of retention basins, canals, pumps, spillways and small diversion dams to prevent unmanageable backups of rainwater on properties to the north.

If water pooled on the freeway, ADOT could quickly pump it into a channel running parallel to the 60. Meanwhile, city storm drains would send water to a string of retention basins along the freeway. Depending who had available water-storage space, Mesa could direct water from its basins into ADOT's canal and vice versa.

The concept — which would keep water off the freeway, out of homes and available to local parks for irrigation — was sound. But when it came to the system's dimensions, engineers did not plan for storms capable of dumping the volume of water that hit Mesa last September.

They used a "50-year storm" benchmark, which federal disaster experts had already deemed outdated. And it seems they misunderstood even that baseline.

"A 50-year storm is by definition an almost once-in-a-lifetime event," engineers wrote in a 1975 report prepared for the state. "The chances two such storms take place in quick succession seem inestimably small."

But a 50-year storm is not, by definition, a storm that happens only once every 50 years. A 50-year storm is one that has a one-in-50, or 2 percent, chance of happening in any given year.

And while a 50-year storm doesn't always generate a 50-year flood — other factors such as soil saturation contribute — the two ideas are directly linked. The 50-year flood standard refers to floods with a 2 percent chance any year.

In 1973, the National Flood Insurance Program had set a 100-year flood — that is, a 1 percent chance in any year — as the standard for federal disaster-relief and preparedness funding, as well as insurance underwriting. Federal agencies use the same minimum today.

It's not easy or cheap to overhaul an insufficient drainage network, but aggressive monitoring and advanced technology can sometimes bolster outdated infrastructure. In systems in other states, for instance, gates that control water flow can be programmed to open and close automatically, and gauges can monitor water levels and flows.

In Mesa, city and state officials primarily use their eyes and hands to control the system.

City inspection records show a Mesa employee making regular rounds checked on the Emerald Park basin the day before the flood. A detailed report was not available, but the absence of work orders issued that day suggests the inspector deemed everything in working order.

A day later, the park was underwater, and the flood was creeping beneath Karen Gleason's front door.

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Her feet planted in the damp carpet, Karen looked across the room and saw the baffling stream of water begin to rush in more rapidly.

She sprinted to the bathroom and grabbed the biggest, thickest towel she could find. She hurried back to jam it under the door, trying to hold off what was quickly becoming a torrent of dingy water.

She raced to the kitchen next, slamming closed the sliding doors that led to a sunken patio.

Still not grasping what was happening, she ran to the hallway, thinking she would seal the doors to the bedrooms, bathroom and office.

The doors would be no use. Rivulets were already unfurling across carpets and reaching up the walls of every room.

Water kept coming.

There wasn't much more she could do inside, so she decided to see what was going on outside.

She opened the front door to a scene her "brain didn't quite get."

Karen's cul-de-sac and yard were submerged in 2 to 3 feet of muddy water, her partly soaked neighbors scattered like buoys throughout the street.

Someone's camper trailer had floated down the road and was wedged between her car and garage door, part of which it had already torn off.

Trash was floating down the road and drifting into what had been her home for the past nine years.

"The people that were home during the day were pretty much standing there going, 'What happened? Where is this water coming from?' Because it was not a burst-pipe kind of water," Karen remembers.

"We were just like, 'What do we do? What are we supposed to do?' "

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HOW MESA'S EMERALD PARK WORKS

Like the infrastructure nearby, the neighborhood hit hardest in the September flood — a subdivision called Emerald Acres and other lots west of Emerald Park — was mostly built during the 1970s.

Most houses are simple one-story ranches or clustered patio homes. Some working- and middle-class residents have lived there for three decades or more.

According to a report ADOT commissioned to analyze the flood, the foundations of homes in the area are elevated only a few inches above the street curb, likely because they were constructed when building codes were more lax. This heightens flood risks. The current standard in Mesa and elsewhere is at least 12 inches.

The Emerald Acres area is not unique; other older or unincorporated neighborhoods in the Valley don't meet modern-day elevation minimums.

So Karen's neighborhood might not have fared so miserably, were it not for the fact that parts of the area were graded against Mesa's natural east-to-west slope.

Water droplets that fall on the east side of town typically flow west. But in the area around Emerald Park, the report says, the neighborhood is graded like a bowl.

The Emerald Acres area can manage ordinary storms fine, as that bowl drains into the park and nearby basins. When a huge amount of water enters the zone, though, the water fills the bowl. And it keeps rising until it gets high enough to spill over the edges.

The ADOT report plainly describes the phenomenon:

"When the capacity of the Emerald Park Basin is exceeded (and) storm water overtops Harris Drive and flows into the Emerald Acres (area), the subdivision may be inundated by several feet of storm water before it can 'break out,'" it says. "The grading of the development, adjacent roadways, and the land adjacent to the US 60 channel determine the extent of the ponding."

When the "ponding," or pooling of water, is severe as it was Sept. 8, there's no explicit plan regarding what to do.

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Surveying the spreading swamp around her, Karen still had no idea where the water was coming from. None of her neighbors understood yet, either.

As her daughter joined her outside, Karen started to fret about what might be in the water. More scraps and debris were gliding across her yard and into her home, and her next concern was about the mold that might come once the water was gone.

It's only a matter of time until the city helps us make things right, she thought.

When Karen and Sofia walked back inside, the water was 6 inches deep — belly-high for their black-and-tan Chihuahua, Iggy, and shaggy West Highland white terrier, Walter. They scooped up the dogs and perched them on the furniture until they could think of a better solution.

The power was still on, and Karen began to worry about electrocution. Not sure what to do, she moved from room to room, cutting off power to ground-level outlets.

As the minutes ticked by, her initial panic ebbed and she began to focus.

She found the insurance documents she could salvage. She grabbed her phone. She climbed onto the raised sleigh bed in her bedroom, where Sofia was already sitting, and started dialing.

She called her homeowner's insurance to report the crisis.

She called her out-of-state relatives to tell them what was going on.

She called a niece living nearby to see if she could take the pair in for the night.

Knowing her neighbor, Tim, was already contacting the city for help and an explanation, she left that call to him.

For hours, she waited.

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Mesa and ADOT officials, too, thought the chaos of the morning storm was behind them when the inundation of the Emerald Acres area began.

By lunchtime, they had responded to hundreds of emergency calls. But when a local television reporter called and alerted officials to the flood, things in the field had been quiet for hours.

Crews from both agencies soon flocked to where the Emerald Park basin met the ADOT channel, wading into waist-deep water. Shoulder-to-shoulder, they piled sandbags along the chain-link fence running across the concrete spillway between the basin and canal, trying to slow the water flowing into the basin and into the waterlogged neighborhood.

They wrestled with the channel gate, attempting to allow more water to pass through.

Manually turning a wheel usually raises or lowers such metal gates, letting water flow downstream or diverting it into the park. But in photos and video from that afternoon, firefighters appeared unable to open the Emerald Park gate by hand. Other photos show a chain and padlock on the wheel that controlled the gate.

Crews brought in a backhoe to help remove channel debris and eventually rip out the gate.

At the same time, ADOT and Mesa officials at command centers were exchanging a flurry of calls and messages, trying to identify precisely where the water was coming from and whether either agency could do anything more to alleviate the flooding.

E-mails from that day indicate Mesa believed water ADOT had pumped off the freeway was at least partly to blame for the flooding, while ADOT told Mesa the flooding was "NOT water from the ADOT highway system but, rather, water from an overloaded city of Mesa drainage basin ... being pumped out."

Public-information officers also debated the details of the message each was presenting to reporters and the public, ultimately agreeing to present a united front focusing on how the "unprecedented amount of rain" had simply been "too much for the retention basins and channels along the U.S. 60 to handle."

As night approached, officials in heavy boots and rain slickers began going door to door, urging those still in their homes to find a dry place to stay. Many residents refused to abandon their homes even temporarily.

Karen and Sofia had made plans to stay with Karen's niece for the night, but they had no way to get there. Finally, sometime after 8 p.m., a neighbor with a truck tall enough to safely drive through the floodwater helped them out.

On Sept. 9, the neighborhood awoke still underwater. Soon, fire crews were using about a dozen industrial-size pumps to move water out of the neighborhood, assisted by huge vacuum trucks that officials said could suck up 1,500 to 2,000 gallons and drive it out.

It took until that afternoon to make visible headway; until the next day to clear out most of the remaining floodwater; and until several days after that before the Emerald Park basin was empty again.

Residents would spend the next year trying to deal with the aftermath.

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By the time Karen could return to check on her home, nearly everything she owned had been destroyed.

Some things — the irreplaceable Middle Eastern rugs passed down to her by her parents, the shoe collection carefully cultivated over the years, the antique chairs, the 75-year-old jewelry box — she would never get back.

Karen grabbed the few pieces of clothing and documents she could. She and Sofia could stay at Karen's friend's house, she thought, just until her homeowner's insurance came through with enough money to help overhaul her home.

They ended up sharing a spare room there for more than six months.

Not only did her insurance company reject her claim, Karen said, it gave her deadlines to get the home back up to snuff. The city, which at first had helped coordinate cleanups and press conferences to answer residents' questions, clammed up given the legal action pending against Mesa and ADOT.

"You really feel for people when you see communities like this, because I'm guessing most people didn't know they had a flood risk," said Robert Traver, storm-water expert and professor at Villanova University.

Traver analyzed the response to Hurricane Katrina on behalf of the American Society of Civil Engineers in 2007 and identified several factors the smaller-scale Mesa disaster shared, including officials "not looking at what happens in a larger (more than 50-year) storm, not communicating to residents the consequences of that storm (and) not understanding the system in totality."

"What you have to do is get the hydrology right," Traver said. "Then, you have to notify people so they can do things: raise their floors, make evacuation plans, not develop in those areas."

Other possible preparedness measures include using building materials that resist corrosion and decay after touching water; filling, regrading and reinstalling poor storm-drainage facilities; and ensuring there will be at least one passable road into and out of a flood-prone area when potent storms hit.

City and state officials could create a more comprehensive contingency plan that includes preparations for bigger, more powerful storms, or they could buy out residents living in the most vulnerable areas and start over, Traver said.

If they do neither, he said, Mesa's history will repeat itself.

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Ultimately, it was volunteers who helped Karen, not any official agency.

After seeing her case in the news, a married couple with a background in humanitarian relief rallied a network of assistants. They descended on the home for three weeks, ripping out and replacing drywall and flooring at no cost.

Though the garage and patio room still need to be repaired, Karen and Sofia were able to return home in March.

"It's been very hard, but I've seen much more of the best in humans than the negative since the flood happened," Karen said in the weeks leading up to the flood's one-year anniversary Tuesday. "I don't want to sound like I pity myself, because so much good came out of it."

Mesa and ADOT have taken some steps to improve the drainage system since last year, formally analyzing its performance, installing cameras to help monitor water flow in real time and offering grant funding to eligible homeowners in the interim.

Earlier this year, Mesa applied for Maricopa County Flood Control District funding to help cover the cost of five drainage projects, including one at Emerald Park expected to begin in 2016. Proposed plans include adding a "bleed-off" line for a storm drain, increasing the capacity of two detention basins and incorporating an "overflow structure" to send extra water back into the ADOT channel.

There's a chance the still-pending lawsuit, in which Karen and more than 100 neighbors are involved, could force officials to do more. Residents are seeking a combined $13.6 million in damages, but those interviewed by The Republic say what they want most is a guarantee they won't see a repeat of last year's devastation.

"I'm immensely anxious about everything we've been able to fix washing away," Karen said.

While it could be years before a verdict or settlement is reached, daily reminders of the flood are inescapable.

In Karen's living room, a stack of paintings taken down after the disaster still rests in the corner. A barely salvaged storage trunk, paint peeling, waits to be mended nearby.

From her driveway, she can see the words spray-painted in tall white letters across the shingles of her neighbor's roof: "FLOOD ZONE?"

And when brief but forceful monsoon storms swept the Valley last Sunday and Monday evenings, Karen and other residents checked the neighborhood's streets and basins again and again, their nerves jittery until hours after the downpour had stopped.

At Emerald Park, they saw city pumper trucks sitting in the rain, waiting.